Hood organization for use with converters employed in steel making process



June 6, 1967 H. J. BLASKOWSKE 3,323,495

HOOD ORGANIZATION FOR USE WITH CONVERTER EMPLOYED IN STEEL MAKING PROCESS Filed Aug. 13, 1963 5 Sheets-Sheet 1 FIG.!

J n 6. 1 67 H. J. BLAfiSKOWSKI 3,

HOOD ORGANIZATION FOR USE WITH CONVERTER EMPLOYED IN STEEL MAKING PROCESS Filed Aug. 13, 1963 5 Sheets-Sheet 2 June 1967 H .1. BLASKOWSKI 3,323,495

HOOD ORGANIZATIOfi FOR USE WITH CONVERTER EMPLOYEDv IN STEEL MAKING PROCESS Filed Aug 15, 1963 5 Sheets-Sheet :5

N w Q g $4 N g Q Mm 6 W? H. J. BLAsKOWSKa 3g3fi3ww53 HOOD ORGANIZATION FOR USE WITH CONVERTER EMPLOYED IN STEEL- MAKING PROCESS Filed Aug 15, 1965 June 6. 1967 H. J. BLASKOWSKI 3,323,495

' HOOD ORGANIZATION FOR USE WITH CONVERTER EMPLOYED IN STEEL MAKING PROCESS FiledAug. 1a, 1963 5 Sheets-Sheet 5 FICSJO F'IC3.I2 2 4' 4, 4

I I ll I. o Q 0 United States Patent 3,323,495 HOOD ORGANIZATION FOR USE WITH CON- VERTERS EMPLOYED IN STEEL MAKING PROCESS Henry J. Blaskowslri, Simsbury, C0nn., assignor to Combustion Engineering, 1336., Windsor, Conn., a corporation of Delaware Filed Aug. 13, 1963, Ser. No. 303,210 11 Claims. (Cl. 1227) This invention relates generally to the combination of a converter within which a process for the manufacture of steel is carried out and a hood or duct organization for conveying the gas generated in such process and egressing from the converter to a desired point of discharge While at the same time extracting a substantial portion of the heat from said gases with burnables in the gases being burned during their traverse of the hood. The present application is a con-tinuation-in-part of US. patent application Serial No. 157,669 to H. J. Blaskowski entitled, Improved Hood Organization for Use With Converter Employed in Steel Making Process, now abancloned.

There is presently a trend in the steel making industry to convert to a process which, among other identifying names, is referred to as the basic oxygen process. Among the characteristics of this process is the introduction of oxygen into an upright, pivotally mounted, converter with there being very large quantities of extremely high temperature gases egressing from the open, upwardly directed mouth of the converter with these gases containing a very high percentage of combustible. Illustrative of these characteristics; the temperature of the gases will be in the range of 3,000 P. and the gases will contain in the neighborhood of 80% carbon monoxide (CO). It is desired that the combustible in this efiluent from the converter be substantially completely burned, and it is further desired that the equipment which conveys this efiiuent to the desired point of discharge be as long lasting and as trouble free as possible. It is further desired to usefully employ as much of the heat contained in these efliuent gases and generated by burning of the CO therein as possible. The organization of the present invention accomplishes these and other advantageous objectives and provides an economic, eificient arrangement which permits the necessary access to the converter as is required for maintenance operations.

It is an object of the present invention to provide an improved hood organization for use in combination with a converter as employed in the steel making industry.

It is a further object of the invention to provide such a hood converter combination wherein a steam generator organization is employed in a manner to provide an improved, long lasting, hood construction within which the burnables in the efiluent from the converter may be burned and where a substantial portion of the heat contained in the gases and produced by the burning of the burnables is absorbed and converted to steam for use as desired.

It is another object of the invention to provide a hood construction having fluid cooled walls and arranged to have a readily removable panel forming a wall portion.

Still another object of the invention is to provide a protective lining for those tubes positioned within an area of the hood that is subjected to molten metal splatterings from the mouth of the converter.

Other and further objects of the invention will become apparent to those skilled in the art as the description proceeds.

With the aforementioned objects in view, the invention comprises an arrangement, construction and combination of the elements of the inventive organization in such a manner as to obtain the results desired as hereinafter more particularly set forth in the following detailed description of an illustrative embodiment, said embodiment being shown by the accompanying drawings wherein:

FIG. 1 is in the nature of a vertical sectional view of the organization of the invention;

FIG. 2 is an elevational view of the removable tubular panel portion of the hood or duct wall located immediately above the mouth of the converter with this view being taken generally from line 22 of FIG. 1 with the wall portion outwardly of the tubes being removed so that the disposition of the tubes may be shown;

FIG. 3 is a transverse sectional view of the hood of the invention taken generally from line 33 of FIG. 1;

FIG. 4 is a transverse sectional view of the removable panel portion of the hood and showing the juncture of this panel portion with the stationary wall portion of the hood;

FIG. 5 is an enlarged detailed view of the portion of FIG. 4 in the circle identified as 5;

FIG. 6 is an elevational view of a modified panel construction which forms part of the hood or duct;

FIG. 7 is a sectional view taken generally along line 77 of FIG. 6;

FIG. 8 is a fragmentary transverse section through the modified panel organization and is taken generally from line 8-8 of FIG. 6;

FIG. 9 is a fragmentary perspective view of this modified, pivotally mounted, panel construction;

FIG. 10 is a cross sectional representation of a typical panel section in the lower portion of the hood illustrating one form of protective lining;

FIG. 11 is an isometric representation of the organization shown in FIG. 10;

FIG. 12 is a cross sectional representation of a typical panel section in the lower portion of the hood illustrating another form of protective lining; and

FIG. 13 is an isometric representation, partly in section,

of the organization shown in FIG. 12.

Referring now to the drawings, wherein like reference characters are used throughout to designate like elements, the illustrative and preferred embodiment of the invention as depicted therein includes the converter or furnace 10 within which the so-called basic oxygen steel making process is carried out for the manufacture of steel. This converter is pivotally mounted on suitable trunnions about the access 12 and is tiltable from its upright, solid lined, position to the position shown in dotted lines where it receives pig, flux, and other material through the chute 14 and is thereafter moved to the upright position where the steel making process is carried out. After completion of the process the converter 10 is tilted about its access 12 in the opposite direction with the molten steel being poured from the mouth of the converter into a suitable receiving vessel.

During the steel making process, oxygen lance 16, which extends downwardly from the housing 18, is lowered into the converter 10 with oxygen being supplied from the lower end of this lance to the material in the converter. While the steel making process is being carried out in the converter 10, large quantities of gas pass from the upwardly directed mouth 20 of the converter with these gases being in the neighborhood of 3,000 F. and containing about 80% CO, as previously mentioned. These gases are received by and conveyed to a desired point by means of hood or duct identified generally as 22.

The hood 22 is inclined, as disclosed, at least in the lower region thereof in order to facilitate access to the interior of the converter for maintenance purposes. The lower or inlet end 24 of the hood 22 is positioned above and spaced slightly from the mouth of converter 10 so that the gasses egressing from the converter enter the hood and pass upwardly therethrough. In passing up through the hood 22 the CO in these effluent gases is burned with the oxygen necessary to support combustion of these gases being introduced into the hood at the lower end thereof through the area that surrounds the upper end of the converter 10' and also in the zone identified as 26 with an air distribution arrangement being provided at this zone as described hereinafter.

As a result of the very high temperatures of the gases that are introduced into the lower end of hood 22 and as a result of the burning of the large quantity of burnable in these gases, a large amount of heat is thus available and the operating conditions in the duct or hood are quite severe. In order to provide a hood construction which will withstand these severe conditions and in order to make available for useful purposes a substantial portion of the heat available in the gases passing through the hood, the hood has its walls lined at the inner surface With steam generating tubes which are connected into the circuit of a, so-called, controlled circulation steam generator.

In a controlled circulation steam generator, water is forced through the steam generating tubes by means of a pump with suitable means, such as orifices, being. provided to distribute the water to the various tubes so that each of the tubes will receive an adequate flow. In the passing up through the steam generating tubes a portion of the water is converted to steam and the steam and water mixture that is developed passes through a drum wherein the steam is separated from the water with the steam being conveyed to a desired point of use while the water is returned to the steam generating tubes along with feedw'ater that is introduced into the drum by means of the circulating pump.

In the illustrative organization the steam and water drum is identified as 28. Feedwater is supplied to this drum as through conduit 30 from a source not shown and boiler water is withdrawn from the drum through the downcomer 32 which is connected with the inlet of pump 34. This pump discharges through conduit 36 to the distribution header 38. From this header 38 the boiler water is conveyed to the header 40 through connecting conduits 42 with this header 40 having connected therewith the inlet or lower ends of steam generating tubes 44. These tubes 44 extend longitudinally of and line the entire inner surface of the hood 22 with the exception of the portion of the hood wall formed by the removable panel 46. This removable panel has its inner surface lined with steam generating tubes 44a arranged in the same fashion as tubes 44 and which are connected at their lower or inlet ends with inlet header 48 and at their upper ends with outlet header 49, both of which headers are mounted on and form part of the removable panel. Water is supplied to header 48 from distribution header 38 through connecting conduits 51 similar to those identified as 42. The lower ends or inlets of the tubes 44 which line the duct wall portion or region above the panel 46 are connected with inlet header 50 which receives boiler Water from distribution header 38 through the connecting conduits 42a.

The steam generating tubes 44 are in side by side generally tangent relation as best shown in Figs. 3 and 5, with adjacent tubes preferably being welded together throughout their length to provide a rigid and generally fluid tight structure, extend up along the inner wall of hood 22. The tubes 44 are connected at their upper ends with the outlet header 52 which is in turn connected with the steam and water drum 28 through the connecting conduits 54. The steam generating tubes 44a which line the inner wall of the removable panel 46 and which are also in generally tangent relation and preferably welded together throughout the height of the panel, are connected at their upper end with the outlet header 56. This header is in turn connected with the steam and water dnlm. 28 through the connecting conduits 54a.

Accordingly, a complete circuit is thus formed with pump 34 being effective to provide a positive circulation of the boiler water through the steam generating circuit. Orifices are preferably provided at the inlet of each of the steam generating tubes 44 and 44a so that assurance will be had that a desired flow throng-h each of the tubes will be maintained thereby providing for eflicient heat pickup as well as insuring against overheating of any of the tubes. Rather than orificing each tube inlet, the supply headers may be sectionalized and the tube connecting with each section may then be orificed. In either event a control of the flow distribution is provided with the size of the orifice being preselected for each tube or tube group.

Upon entering the steam and water drum 28 the steam and water mixture produced in the steam generating tubes is separated with the steam passing to the upper portion of the drum and out the conduit 58 while the water is returned through the downcomer 32.

As previously mentioned, hood 22 is inclined as disclosed to permit access to the interior of the converter 10. This is essential because it is periodically necessary to rebrick the converter, such as after every week or so of operation, and to accomplish such maintenance operation equipment must be lowered down into the converter through the upper end thereof. By inclining the hood 22 and making the panel 46 removable, this is readily accomplished. As disclosed in FIGS. 1, 2 and 4, the removable panel 46 has a substantial circumferential dimension as well as a substantial longitudinal dimension providing a relatively large opening through which the necessary equipment may be lowered down into the converter 10. It is desired that the necessary maintenance operations be carried out as quickly as possible so that the converter may be placed back in operation and for this reason, the removal of panel 46 must be a relatively simple operation. This is readily accomplished with the organization of the invention and it is for this purpose that there is interposed in the connecting conduits 51 and 54a, a readily detachable coupling 58 which, as illustratively disclosed, includes a pair of flanges which are bolted together. Any quickly removable coupling, however, will fulfill the desired purpose. On each side of the coupling 58 in each of the connecting conduits 54a and 51 there is provided a shut off valve 60. When the panel 46 is removed, these valves 60 are closed so that neither the panel nor the other portions of the steam generator need be drained in order to remove the panel.

The panel 46 is retained in its desired position by means of suitable removable clamping members which retain the panel against stop members which are not shown in the drawing. The clamp members disposed at the sides of the panel include the lever 62 pivotally mounted on stud 64 which is retained in the outer flange of channel 66. This channel is mounted on the stationary portion of the hood 22, being secured to plate 68 which is in turn secured to the tubes 44 and the outer skin casing member 70. There is a complimentary channel 72 mounted on the removable panel 46 with this channel 72 being secured to a plate 74 which is in turn secured to the tubes 44a and the outer skin casing of the panel and which is identified as 70a. The lever 62 is effective to secure in place the bridge plate 76 which bears against the outer flange of each of the channels 66- and 72 and accordingly retains the panel 46 in place against the aforementioned stops. Since the hood interior is slightly below atmospheric pressure during operation, a small amount of air leakage into the hood around panel 46 is of no consequence so that a fluid tight fit of the panel does not have to be provided.

In order to accommodate the oxygen lance 16 the tubular members 440: at the centermost region of the panel 46 are bent as disclosed in FIG. 2 to provide an opening 78 which may receive and have the lance 16 pass therethrough.

It will be appreciated that when it is necessary to provide access to the converter for maintenance purposes the oxygen lance 16 will be raised so that it is completely withdrawn from the opening 78 in panel 46. Thereafter the valves 6%) will be closed, couplings 58 will be disconnected and the lever 62 moved to release the bridge plates 76. A crane may then lift the entire panel 46 from the hood 22 after which the necessary maintenance equipment lowered into the converter 10.

As illustratively disclosed the upper end of the hood or duct 22 includes an extension 80 which may extend a substantial vertical distance with this vertically disposed extension being connected with the inlet of induced draft fan 82 which is driven by motor 84 and which is effective to draw air up through the duct or hood 22.

As previously mentioned, at the location 26 air is introduced into the hood 22. This is accomplished by means of the distribution duct 86 which is supplied by air from the motor driven fanSS and the breeching 90. Extending from the duct 86 are a plurality of nozzles 92 which are arranged to direct streams of air tangent to an imaginary cylinder 93 which is coaxial of the hood 22 as disclosed in FIG. 3. This introduction of air at the zone 26 in the manner disclosed has a number of advantageous aspects; first, it provides, as a result of the swirling motion created within the hood 22, a very turbulent region thereby tending to produce a more intimate mixture of the combustion supporting air and the CO so that more efficient combustion of the CO is obtained. Secondly, this tangential introduction of combustion supporting air provides for a more even distribution of the heat absorption throughout the tubular wall surface of the hood. This is so because there is a tendency for there to be a very non-uniform heat absorption in the hood as a result of drawing air into the lower end of the hood. This uneven heat absorption is extremely undesirable since it will tend to cause overheating of the tubular elements in the region of the highest absorption while the tubular elements in the region of the lower absorption will be relatively ineffective. The high turbulence created by the tangential air introduction provides a much more even heat absorption distribution than would otherwise be possible. Thirdly, and most important, is alleviation of the problem of degradation of the steel product caused by nitrogen entering the converter during its operation. This isachieved by means of the supplemental introduction of combustion supporting air at zone 26 because by means of this supplement-a1 air introduction the chances of eddy currents forming at the mouth of the converter and which will be of sufficient intensity to cause nitrogen to be introduced into the converter are greatly reduced over the possibilities of such eddy currents forming if all of the air necessary for the combustion of the CO in the converter effluent were introduced into the hood 22 at the lower region thereof and between the mouth of the converter and the entrance of the hood. It is the action of induced draft fan 82 which draws the combustion supporting air into the entrance of the hood. This fan requires and accordingly pulls a fixed quantity of gas and air through the duct and therefore by introducing combustion supporting air at zone 26 the amount of air that enters the duct at the entrance thereof between the lower end of the duct and the converter 10 is reduced by the amount equal to the quantity of air introduced at the zone 26. By thus reducing the amount of air entering hood 22 at the entrance 24 the chances of eddy currents developing and accordingly the chances of degradation of the steel product due to nitrogen traces is reduced.

In addition to providing for introduction of air at the zone 26 and in a tangential direction as described it is also desirable to introduce fuel into this zone 26. For this purpose, there is provided a fuel supply pipe 94 which is disclosed in FIG. 1 and from which extends suitable nozzles 96 adjacent the air nozzles 92 to introduce fuel in the same direction as the air. In the illustrative organization fuel is preferably supplied to hood 22 from the fuel supply conduit 94 in order to bring the temperature of the tubular members 44 and 44a up to their operating temperature in a gradual manner before the hot blast from the converter is received from the hood. It is undersirable to subject the tubular lined hood 22, when in its cold condition, to a hot blast from the converter 10. By means of burning fuel in the manner aforemen tioned and activating the pump 34 to circulate the water through the steam generator the steam generating tubes may be brought up to their saturation temperature prior to receiving a hot blast of gas from the converter. It should further be pointed out that, if desired, supplemental fuel may be introduced into the hood 22 during operation to increase the steam generated capacity of the steam generator. And in this connection the extension may also have its walls lined with steam generating tubes and in addition convection heating tubes, in the form of tube banks, may be disposed within the extension duct 80 to form a relatively high capacity steam generator. This may be desirable in instances where relatively large quantities of steam are desired with the steam demand being greater than that produced by means of the efiluent from the converter vessel.

It should be noted that by introducing tangential air at the zone 26 and providing a tubular region where complete combustion will be provided resulting from the intirnate mixing of the CO and the air the danger with regard to explosions in the duct work downstream of this air introduction zone will be greatly reduced. This is so because the combustibles will be consumed and will not collect in pockets where explosions may occur.

The hood 22 is of rigid construction having a steel framework which is comprised of longitudinally extending I beams 98 and transversely extending I beams or buckstay members 100 which are interconnected with said beams 98. The entire hood is supported from above from the structural support members 102 and 104 with there being suitable handers such as 106 extending from these structural members, or in the case of member 104 extending from suitable steel structure supported on this member. These handers are connected with members which are rigidly secured to the hood.

In the organization of the invention it is essential that there be provided a forced circulation of the fluid medium through the tubes 44 and 44a. This is essential because of the extremely severe operating conditions that prevail within the hood. If this positive circulation is not provided but natural circulation relied upon entirely, overheating of tubes in certain locations in the hood will occur causing failure of these tubes and costly maintenance operations. With the organizations of the invention not only is a positive circulation of fluid through the tubes 44 and 44a provided but by means of the orifices a proper distribution of the fluid medium to these tubes is facilitated thereby further insuring that adequate cooling of all of the tubes is had.

In lieu of constructing the panel in the manner disclosed in FIGS. 2, 4, and 5, wherein the panel is removed from the duct by means of a crane or other apparatus, the panel may be pivotally mounted to the duct so that it may be pivoted from a closed position when it is necessary to provide access to the converter or furnace 10.

The modified organization of FIGS. 6 through 9 discloses such a pivotally mounted panel. In accordance with this modified arrangement the tubes 44a of the panel are connected at their upper and lower ends to supply return headers 110 and 112. The panel of this modified organization is divided into two sections 46a and 46b and each section is mounted upon suitable pivot supports identified as 114. In order that these panel portions may be pivoted between closed and open positions there are provided flexible supply conduits 116 and flexible discharge conduits 118. The supply conduits have their inlets connected with the supply header 48a and their outlets are connected with the header 110 with this header being in two sections as disclosed and with one of the conduits 116 supplying each half of the header. The flexible conduits 118 are connected at their inlet ends with the header 112, Which is formed in two sections in the same manner as header 110, and have their outlets connected with the header 50. The panel is provided with structural support members 120 which, together with the tubular lining on the inner surface of the panel, provide a rigid construction that may be readily moved about the pivots 114. These pivots include the structural members 122 which are secured to the outer portion or surface of the panels and which together with the protrusions 124 mounted on channel 126 receive the pivot pin. The two halves of the movable panel are retained in their enclosed position by means of a suitable lock which includes plate 128 with which the locking arms 130 cooperate to retain the panel halves in place.

With this panel arrangement the pump 34 is effective to force the boiler water through the panel from the supply header 48a with the water entering the header 110 from the flexible conduits 116 and passing up through the longitudinally extending tubes 44a that line the panel. This fluid which is collected in the header 112 at the upper end of the panel is conveyed from this header through the flexible conduits 111 8 to the header 50 from which it passes through the tubes 44 lining the corresponding upper portion of the hood.

With this pivotally mounting panel organization the panels may be readily moved from a closed position where they are in line with the remaining wall portion of the hood to an open position wherein the area of the hood wall occupied by the panel is open to permit access to the interior of the converter as previously described.

The above constitutes the disclosure presented in the parent U.S. patent application, Serial No. 157,669 of which the present application in a continuation-in-part.

It has been found that, while the converter hood arrangement described in the parent application is capable of effectively conducting gases generated in the converter under normal operating conditions, the basic oxygen process described in that application is characterized by intermittent eruptions of the contents of the converter vessel which cause molten metal to be blown from the converter onto the tube panels located in that portion of the hood adjacent the inlet thereof that overlies the open mouth of the converter. The molten metal splatterings which are of the order of 3000 P. in temperature subject the tubes to a high rate of heat flux in the localized areas affected by the splattering. This heat flux causes the tubes to experience temperatures far above the 750 to 900 F. temperatures which they are capable of withstanding and therefore result in the rapid corrosion of the tube material thereby requiring frequent shutdowns of the hood and with it, the converter, while the tubes are repaired or replaced.

In order to alleviate this problem, it has been contemplated to coat the affected portion of the hood with various forms of furnace refractories. Such coating has,

however, met with little or no degree of success since conventional refractories and other thermal insulating materials are incapable of withstanding the tremendous amount of heat flux to which they are subjected by the molten metal splatterings for any extended period of time before deteriorating themselves. Moreover, it has been found that such materials, being thermal insulators, are ineffective in protecting the tubes due to the fact that they absorb and retain the heat within the affected area for a period of time that permits an excessive amount of heat to be realized by the underlying tubes.

The subject matter of the present continuation-in-part application provides an effective means for protecting the steam generating tubes which line the inner surface of the hood in the area subjected to repeated molten metal splatterings caused by the aforesaid converter eruptions. The improvement comprises lining the affected portion of the hood with a protective lining of heat dissipating material which is capable of preventing the tubes from experiencing surface temperatures of greater than that which they are designed to withstand and, at the same time is capable of withstanding the effects of the molten metal splatterings for at least as long as a normal converter campaign, which is defined as the length of time the converter can be continuously operated as usually dictated by the life span of the fire brick lining of the vessel.

With reference to the drawings, the area of the inclined hood that is affected by the molten metal eruptions occurring within the converter vessel is that indicated in FIGURE 1 as the shaded area 140. It is the tubes 44 and 44a in this portion of the hood that are splattered with the molten metal and which sustain an excessive amount of heat flux :which results in their rapid deterioration and failure. In accordance With the present invention these tubes are covered by a protective lining 142 formed of a material that is a relatively good heat conductor and which is itself capable of withstanding the corrosive effects of the metal splatterings. The lining is constructed in two layers, the inner layer 144 or 144' which is in intimate contact with the tubes 44 or 44a, being formed of aluminum, and the outer layer 146 or 146' consisting of replaceable splash plates.

Aluminum is employed as the inner layer 144 because of its excellent ability to conduct heat but, since it is easily corrodable by repeated splashing of the molten metal, it too must be protected. For this reason, a covering for the aluminum is provided by means of the splash plates 146 and 146'. These plates are formed of nodular cast iron which exhibits relatively good heat conducting characteristics and is also capable of withstanding for an extended period of time the harmful corrosive effects of repeated splatterings of the extremely high temperature metal. The splash plates 146 and 146, while being not completely immune to corrosion, are capable of functioning as heat dissipators for at least as long as a converter campaign. At the end of a campaign these plates which have been partially eaten away by the molten metal can be replaced while the converter vessel is being relined. Therefore, by means of the protection afforded the tubes the converter need not be shut down prematurely and no attendant loss in production is realized.

The structural arrangement of the protective lining is as shown in FIGURES 10 through 13. In the embodiment shown in FIGURES l0 and 11 the inner layer 144 comprises aluminum sleeves which are bonded to and enclose the tubes 44 or 44a in the affected portion of the hood 22. Covering the tubes 44 or 44a and sleeves 143 are a plurality of nodular cast iron splash plates 146 which contain arcuate recesses 149 on their inner surface in order to effect intimate contact between the plates and the outer surface of the sleeves. The splash plates 146 are retained in place by means of studs 150 which are mounted therein and threadedly fastened to backing strips 152 on the rear side of the tube panel thereby facilitating their disassembly when it is necessary to replace the plates. As shown in FIGURE 11, the plates contain bosses 154 and adjacent recesses 156 which receive the bosses 154 to achieve an interlocking structure and thereby present a continuous surface having no spaces through which molten metal or heat can pass. Insulation 160 and skin casing 70 is applied to the rear side of the tube panel to complete the structure.

In FIGURE 12 is shown another embodiment of the protective lining contemplated by the invention. This arrangement includes splash plates 146 formed with aligned lugs 164 projecting from the rear surface of the plates. In constructing the tube panel tubes 44 are mounted between the lugs 164 and molten aluminum 144 poured thereabout. The aluminum thus becomes bonded to both the tubes 44 and the inner surface of the plates 146' thereby presenting a good thermal barrier. When it is desired to replace the plates 146', heat is applied to loosen the bond and the spent plate is removed and a new one inserted.

During normal operation of the converter the temperature of the gases rising from the vessel create a surface temperature of approximately 1400 F. within the hood. This heat is dissipated in the outer layer formed by splash plates 146 or 146' such that the heat realized by the outer surface of the inner protective layer is approximately 520. The inner layer further dissipates the heat throughout its mass so that the temperature finally realized by the surface of the tube 44 is approximately 480, a temperature which the tubes can readily withstand. When eruptions occur within the converter vessel 10 and molten metal splatterings are experienced within the hood 22 these splatterings, having a temperature in the order of 3000 F., first contact the cast iron splash plates 146- or 146. The temperature at the outer surface thereof in the localized area affected by the splattering becomes approximately 2750 F. and, due to the ability of the splash plate material to conduct heat, the heat is rapidly dissipated throughout the lining such that the temperature which reaches the surface of the inner layer 144 or 144' is of the order of 680 F. This heat is further dissipated throughout the inner layer such that the temperature finally realized by the face of the tubes 44 is approximately 590 F., a temperature which is well below that which the tubes are designed to withstand.

By means of the protective lining provided on the inner surface of the converter hood the steam generator organ zation employed to provide an improved, long lasting hood construct-ion within which the burnables and the efliuent from the converter may be burned is protected against the adverse effects of converter eruptions in a manner which prevents shutting down the converter except when it is necessary to replace the vessel lining. The invention therefore makes it possible to operate the converter in a manner in which its protective potential is achieved.

It will be understood that various changes in the details, materials, and arrangements of parts which have been herein described and illustrated in order to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the appended claims.

What is claimed is:

1. A converter hood having an open end for receiving the gaseous effluent from a steel-making converter, the walls of said hood having their inner surface lined with steam generating tubes, means for circulating vaporizable liquid through said tubes and for conveying the steamliquid mixture generated therein from said tubes, means for introducing air into said hood intermediate the extremities thereof including directing means effective to introduce the air tangent to an imaginary cylinder coaxial with said hood so as to create a whirling motion therein and means for introducing fuel to said hood coincident with the streams of air admitted thereto.

2. The organization of claim 1 including induced draft means operative to draw gases through said hood from the open end thereof.

3. The organization of claim 2 including inlet header means connecting said tubes at the lower ends thereof, outlet header means connecting said tubes at the upper ends thereof, uptakes connecting said outlet header means With a steam and water drum, and means including pump means operative to convey water from said drum to said inlet header means.

4. The organization of claim 3 wherein said hood is of circular transverse section there being an air distribution conduit disposed about the hood at a location intermediate the extremities thereof, a fan supplying air to said distribution conduit, means conveying air from said conduit and introducing it into said hood at a plurality of symmetrically disposed locations about the circumference thereof and in a direction tangent to an imaginary cylinder coaxial of said hood.

5. An inclined hood for receiving and conveying the gaseous efliuent from a steel-making converter, said hood having an open lower end for admission of said gases thereto, induced draft fan effective to draw gases up through said hood, a steam generator having steam generating tubes effectively lining the inner surface of said hood, means for introducing air into said hood at a location intermediate its extremities and in a plurality of streams directed generally tangent to an imaginary cylinder coaxial of said hood, and means for introducing fuel into said hood adjacent said air streams.

6. The organization of claim 5 including structural support means disposed above said hood and connected therewith for supporting said hood from above and permitting downward expansion thereof.

7. In combination a converter for producing steel, an inclined hood with its inlet above the converter to receive the gaseous effluent therefrom, a steam generator having steam generating tubes lining the inner surface of said hood and having a pump to establish positive circulation, a protective lining covering said steam generating tubes adjacent the inlet end of said inclined hood, said lining being formed of heat dissipating material and comprising an inner layer of such material bonded to said tubes and an outer layer of such material in the form of replaceable plates.

8. The organization of claim 7 wherein said inner layer of heat dissipating material is aluminum and said replaceable plates are formed of nodular cast iron.

9. The organization of claim 7 wherein said inner layer of heat dissipating material is in the form of aluminum sleeves encompassing and being bonded to each of said tubes and said outer layer is in the form of replaceable splash plates formed of nodular cast iron and having an inner surface in conformity to the outer surface of said sleeves whereby surface-to-surface contact can be maintained therebetween.

10. In an inclined hood having an open lower end for receipt of the gaseous effluent from :a steel-making converter, said open end being disposed above the mouth of said converter, a steam generator having longitudinally extending tubes in side-by-side relation lining the inner surface of said hood, a protective lining covering those tubes positioned in that portion of the hood subject to molten metal splattering from the mouth of said converter, said lining comprising a heat conductive material having sufiicient strength and corrosion resistance to be capable of undergoing an acceptable rate of deterioration when subjected to intermittent localized temperature applications of about 3000 F., said heat conductive material including an inner layer of aluminum encircling said tubes and an outerlayer of nodular cast iron in contiguous relation with said aluminum sleeves.

11. The organization of claim 10 wherein said heat conductive material comprises aluminum sleeves enclosing and being bonded to each of said tubes along the 1 1 effected portion of their length and splash plates formed of nodular cast iron removably attached to the tube panel in contiguous overlying relation to said sleeves.

References Cited UNITED STATES PATENTS 725,746 4/1903 Moore 122-498 X 2,360,855 10/1944 Dow et al. 122-498 2,831,467 4/ 1958' Guczky 122-7 12 3,168,073 2/1965 Durham et al. 1227 3,170,017 2/1965 Namy 1227 FOREIGN PATENTS 5 1,063,191 8/1959 Germany.

KENNETH W. SPRAGUE, Primary Examiner.

ROBERT A. OLEARY, Examiner.

D. G. BLAOKHURST, Assistant Examiner. 

1. A CONVERTER HOOD HAVING AN OPEN END FOR RECEIVING THE GASEOUS EFFLUENT FROM A STEEL-MAKING CONVERTER, THE WALLS OF SAID HOOD HAVING THEIR INNER SURFACE LINED WITH STEAM GENERATING TUBES, MEANS FOR CIRCULATING VAPORIZABLE LIQUID THROUGH SAID TUBES AND FOR CONVEYING THE STEAMLIQUID MIXTURE GENERATED THEREIN FROM SAID TUBES, MEANS FOR INTRODUCING AIR INTO SAID HOOD INTERMEDIATE THE EXTREMITIES THEREOF INCLUDING DIRECTING MEANS EFECTIVE TO INTRODUCE THE AIR TANGENT TO AN IMAGINARY CYLINDER COAXIAL WITH SAID HOOD SO AS TO CREATE A WHIRLING MOTION THEREIN AND MEANS FOR INTRODUCING FUEL TO SAID HOOD COINCIDENT WITH THE STREAMS AIR ADMITTED THERETO. 